Cat Ears

Not long ago, we came home to a very strange sight. All our cats had gatheredaround the refrigerator and were completely entranced by its bottom. On movingthe refrigerator, we found cockroaches! The high-pitched communication of bugsor rodents that falls on our "deaf" ears is music to a cat.

A cat's superb hearing ability begins with the sound-gathering flap called thepinna. The inner surface of the pinna and the beginning of the ear canal (whichyou can see) should be a light pink. You may see a small amount of yellow waxand a few hairs at the canal opening. These act like flypaper, trapping dust, insects,or other potential irritants and guarding against infection. If this area is reddened,foul-smelling, or has a puslike or brown, waxy discharge, an ear infection may bepresent. Your veterinarian can check the rest of the ear with anotoscope, a special instrument equipped with a light source and magnifying lens.

The ear canal is L-shaped, going down (vertical canal) and then in (horizontalcanal). The eardrum is at the end of the horizontal canal. Sound waves (the cock-roach talk, for example) travel down the canal and beat against the eardrum--like stick beating a drum. The cockroach-talk vibrations are amplified in the middle by three small bones called the auditory ossicles, which pass the sound on to the Inner ear's snail-shaped and fluid-filled cochlea via the oval window (a vibrating membrane). The waves produced in the cochlea are converted to electrical sages that travel to your pet's brain via the auditory nerve. Your cat interprets message as cockroach talk and sits in front of the refrigerator, patiently waiting for a roach snack.

Above the cochlea are three small, fluid-filled semicircular canals. These loops of tubing contribute to your cat's remarkable sense of balance. If your cat starts to fall, fluid in one of the canals is displaced. Hair cells in the canals detect be change and immediately inform the cat's brain, which orders muscles to tighten and keep your cat upright.